Human energy system contain Seven Chakras called as energy centers.
The Muladhar Chakra
This is the first chakra the base energy center.The muladhar chakra has two possibilities. Its first potentiality is a natural one that is given to us with birth; its other possibility is obtainable by meditation. The basic natural possibility of this chakra is the sex urge of the physical body. Transformation takes place within as you begin to understand sex.The more the mind is focused upon and gripped by sexual desire, the more difficult it will be to reach its ultimate potential of the energy.
The Swadhisthan Chakra
Basically, its natural potential is fear, hate, anger, and violence. All these are conditions obtained from the natural potential of the swadhishthan chakra.
If a person stagnates at the second body, then the directly opposite conditions of transformation - love, compassion, fearlessness, friendliness - do not take place. The obstacle on the meditator's path in the second chakra is hate, anger and violence, and the question is of their transformation
The Manipuraka Chakra
Primarily, the third Chakra revolves around doubt and thinking. If these are transformed doubt becomes trust and thinking becomes awareness. If doubts are repressed you never attain to shraddha, trust. He who represses his doubts never attains to trust, because doubt remains present within. Doubt and trust are its two forms. Trust is the purest and most ultimate development of it.
The Anahat Chakra
When the heart chakra is open, all energies can flow freely. There are no inner blockades and man feels deeply united with himself and all other creations. Man feels sheltered and radiates warmth, satisfaction and heartiness. Man loves for the sake of love. Lessons for this chakra are unconditional love, trust, compassion and forgiveness.the anahata is just in the middle; three below it, three above it. When a person is just in the middle, on the fourth chakra unconditional love on all living beings happens.
The Vishuddhi Chakra
The fifth chakra is the vishuddhi chakra. It is located in the throat. Wordpower goes high and starts living in truth and tells only truth.
The fifth plane is so blissful that you will not have the heart to leave it and proceed further. Therefore, the individual who enters this plane has to be very alert about clinging to bliss so that it does not hinder him from going further. Here bliss is supreme and at the peak of its glory; it is in its profoundest depths. A great transformation comes about within one who has known himself. But this is not all; there is further to go also.
The Agna Chakra(Third Eye)
Here there is no duality. the experience of existence, of being, on the sixth. The absolute being, is known from sixth chakra.This chakra is connected to the cosmic body. Those who work completely on this chakra will begin to call the vast infinite expanse that they witness the third eye. This is the third eye from where they can now view the cosmic, the infinite. The day your energy passes through this chakra your body and senses start obeying you. You become the master.
The Sahasrar Chakra
The journey to nonbeing, nonexistence starts. The seventh plane is an ultimate death. Nirvana.
==> So on constant practice of meditation the energy starts moving from lower to higher. Everytime it passes through each and every chakra we are filled with more light and will get great insight towards the life and mysteries in the existence will be opened up.